I've been following this chain. And I must say it is pretty entertaining. But I keep waiting for the conclusion. Like a mystery movie, you can't wait until you find out how it ends.
But Winteriscoming, the answer you are looking for is obvious. You wanted a PF. So go after the new one. The whole reason why you bought the first PF is so you can enjoy your pinball. So just do it. Don't let money that has already been spent affect your future decisions. Its water under the bridge.
If you get your money back from the original purchase or if you actually do get the PF, great icing on the cake.
Also do not let this new purchase affect your decision to go after the original seller. You still need to pursue him just as if you never received a PF.
That's my advise.
good luck